摘要
北京时间2017年11月18日06时34分(GMT:2017-11-17 22∶34),西藏自治区林芝市米林县发生了M6.9地震.本次地震位于东喜马拉雅东构造结末端旋转变形强烈部位.本研究基于林芝台阵记录的波形数据,应用双差定位方法和匹配滤波方法对本次地震早期余震序列进行了全面检测分析.截至2017年11月25日上午08时,我们共获得约10倍的中国地震台网公布的余震事件.余震的时空分布特征显示,本次米林M6.9地震余震呈NW向,位于北东向南迦巴瓦构造结北部的东西两侧边界断裂带之间,沿西兴拉断裂带分布,断层具有明显的分段破裂特征,主震位于余震分布带中部.根据余震分布特征以及震源机制解显示,发震断层的深部几何结构为北东向陡倾,主震北东侧的断层活动为主震及发震断层触发的结果,其深部几何结构也较陡,余震整体沿断层分布长度约50km.
An M6.9 earthquake occurred at 06∶34 CST（2017-11-17 22∶34 GMT）on 18 November2017 at Mainling prefecture,Nyingchi city,Tibet.This earthquake is located near the northeastern corner of the eastern Himalayan syntaxis where strong crustal shortening and the tectonically rotated deformation occurred.Based on the waveform data recorded by the Nyingchi Array,we applied the waveform matched-filter technique and double difference earthquake location method to analyze the spatial-temporal evolution of early aftershocks following the main shock.We obtained over 10 times more aftershocks than that in the catalog from the China Earthquake Network Center.Our analysis indicates that the aftershocks are mainly distributed in north-west direction,which are located on the Xixingla fault and between the east and west sides of the boundary fault zone north of the Namcha Barwa syntaxis.The fault has the clearly segmental rupture characteristics and the main shock is located in the central part of the aftershock belt.Combined the results of the focal mechanism solutions,we suggest that the seismogenic fault of this event steeply dips to northeast and its segment to the northeast of the main shock′s epicenter could be triggered by the main shock.The overall length of the aftershocks is about 50 km along the fault.
作者
尹昕忠
周本刚
陈九辉
韦伟
谢超
郭志
YIN XinZhong;ZHOU BenGang;CHEN JiuHui;WEI Wei;XIE Chao;GUO Zhi(State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China;Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration , Beijing 100029, China;Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2018年第6期2322-2331,共10页
Chinese Journal of Geophysics
基金
地震行业科研专项(201508024)
中央级公益性科研院所基本科研业务专项(IGCEA1510,IGCEA1711)联合资助
关键词
米林M6.9地震
微震检测
发震构造
东喜马拉雅构造结
Mainling M6.9 earthquake
Microseismic detection
Seismogenic structure
Eastern Himalayan Syntaxis
